BIOLOGY 1A03 Lecture Notes - Lecture 23: Ribbon Diagram, Endomembrane System, Microtubule

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Kim Dej

Document Summary

Bio 1a03 lecture 23 dr. da silva review. Phospholipids have a hydrophilic head and a hydrophobic tail: the hydrophilic head is polar, and has a phosphate group and a glycerol, the hydrophobic tail has 2 two long fatty acid chains, hence a tail. There are about 16 to 18 carbons in the chain. Tails can be kinked (unsaturated) or not kinked (saturated) Factors that affect the fluidity of cell membranes: There are many factors that affect the fluidity of cell membranes: temperature: the kinetic molecular theory states that molecules vibrate and move faster when the temperature increases. Hence, when the temperature increases, the fluidity increases as well. Conversely, when the temperature decreases, the fluidity decreases as well: cholesterol: cholesterol increases fluidity at low temperature and decreases fluidity at low temperature, number of carbons: the number of carbons in the chain also determines membrane fluidity. Saturated fatty acids on the other hand are packed together tightly, and are hence less fluid.